The objective of this study is to evaluate the safety and efficacy of oral 256U87 (the prodrug of acyclovir) vs acyclovir in the treatment of recurrent ano-genital herpes in HIV infected persons (CD4 > 100). There is no placebo in this study. Efficacy variables include the length of episode, the time to lesion healing, the duration and severity of pain/discomfort, the duration of viral shedding, the proportion of patients with aborted episodes, and the proportion of patients requiring extended therapy.